Well, once you get the time to watch it, you can find Season 3 Episode 1 & 2 in this post.
I never realized that Applejack has never had her own song (barring ones that have everyone from the mane six). Rainbow Dash only has a shared one with Fluttershy from the pet episode, but at least she's got plenty of episodes to herself. Applejack really does get the shaft a lot.
Hopefully there'll be an episode in season 3 that'll give some of the background ponies more spotlight, even if it is just a few lines from each of them. What are you personally hoping for for season 3?
I actually had no idea who Roseluck is or that she existed until you mentioned her and I looked for art of her on deviantart. I knew that there were palette swapped ponies, but I didn't know they were that prevalent in the series. I also found out about another palette swap of Roseluck and Lyra named Seafoam. I recall seeing both Roseluck and Seafoam very briefly in some episodes, but I didn't know they were palette swaps. It's really suprising how different a pony can look just by changing their colour scheme.
Appleblossom is definitely my most favourite among the CMC (the ribbon in her hair is too cute). As for background ponies, my favourites are Lyra (the unicorn with really light green hair and skin) and Snowflake (the muscly, buff pegasus in Hurricane Fluttershy that always screams "YEAH!!!").
Pinkie is a similar case (replacing nerdiness with carefreeness), though I also find her bubbliness amusing, and I like how she can be quite dependable at times (like the babysitting episode and the episode with the elderly donkey). Rainbow Dash, I find her cockiness to be a little too much at times, but I still find her okay.
In order starting with my most favourite, it'd be Fluttershy, Rarity, Applejack, Twilight Sparkle, Pinkie Pie, and Rainbow Dash. Fluttershy is my #1 favourite since she's so sickeningly cute, sweet, and pretty. Rarity is second since I find her somewhat vain and obsessive nature to be kind of cute. That and she's really nice and dependable (and pretty). I also really like how she returns Spike's feelings for her even though she's not the dashing pony she dreamt of being with, and instead appreciates Spike for who he is. Applejack I find adorable with her cowgirl get up and accent. Twilight, I find her nerdiness cute, but I like the other three aforementioned better.
Hi. I hope you stick around and post lots. Out of curiousity? Who's your favourite pony?
